On the use of a microwave linear accelerator for control of carrier lifetime in electronic silicon devices

Abstract

The possibility of using a 12 MeV linear accelerator for control of minority carrier lifetime in silicon power rectifiers and thyristors to be used at high frequencies has been investigated. Electron irradiation of these devices has been used in place of metallic diffusion and ⁶⁰Co gamma irradiation. A comparison with the latter two techniques is made. The relation between absorbed dose and high and low injection lifetimes (τHL and τLL) has been studied for diodes and from the linear relationship $\text{1}\text{τ}\text{=}\text{1}\text{τ}{}_0\text{+ KD}$ found, values for the damage constant have been calculated. The dependence of the stability of the electrical characteristics of the silicon devices after electron irradiation on the annealing process at 150, 200, and 360°C has been analyzed. The conclusions drawn from this study are that charge lifetime control in semiconductors is feasible by high energy electrons because electron irradiation provides the more precise, uniform, and reproducible method of lifetime control. In addition this technique is much better than the conventional metal diffusion or gamma irradiation in raising the quality and end-product rate of these devices.